Millipede-specialist
Guides
Phengodes fusciceps
glowworm beetle
Phengodes fusciceps is a species of glowworm beetle in the family Phengodidae, described by LeConte in 1861. It is found in North America. The species comprises four recognized subspecies: P. f. fusciceps, P. f. floridensis, P. f. intermedia, and P. f. picicollis. Like other phengodid beetles, larvae are bioluminescent and exhibit specialized predatory behaviors.
Phengodes plumosa
glow worm, railroad-worm, Plumose Glowworm Beetle
Phengodes plumosa is a glowworm beetle in the family Phengodidae. Larvae are bioluminescent and predatory, feeding primarily on millipedes. The species is found in North America. Common names include "railroad-worm," referring to the larval pattern of glowing spots that resemble train windows.
Promecognathus
Promecognathus is a genus of ground beetles comprising two described species, P. laevissimus and P. crassus. These beetles are specialist predators of cyanide-producing flat-backed millipedes in the family Xystodesmidae. They possess exceptional physiological tolerance to hydrogen cyanide, surviving doses 7–15 times greater than those lethal to other carabid beetles. This tolerance allows them to attack millipedes directly without behavioral avoidance of chemical defenses, representing the first documented case of cyanide tolerance in predatory insects.
Promecognathus crassus
Straight-jawed Pedunculate Ground Beetle
Promecognathus crassus is a specialist predatory ground beetle endemic to the Pacific coast of North America. It exhibits exceptional physiological tolerance to hydrogen cyanide and benzaldehyde, enabling it to prey on cyanogenic millipedes that are chemically defended against most predators. The species has been documented to withstand cyanide exposures 7–15 times greater than doses that incapacitate other carabid beetles, with individuals remaining active after two hours of high-concentration exposure. This tolerance appears to be a specific adaptation supporting its obligate millipede diet, as the beetles do not employ behavioral avoidance of their prey's chemical defenses.